[3][4] Throughout his four years of training, Yeonjun became known as the company's "legendary trainee" because he consistently ranked first during monthly evaluations in dance, vocal performance and rap.

[17][18] In February 2022, Yeonjun featured on the single "PS5" by American singer-songwriter Salem Ilese, alongside bandmate Taehyun and Norwegian DJ Alan Walker.

[21] In November 2023, he was announced as a co-host for the year-end festival SBS Gayo Daejeon alongside Key and An Yu-jin; the event was held on December 25.

[22] On June 25, 2024, it was announced that Yeonjun would be hosting the SBS Gayo Daejeon's Summer Edition alongside Ive's An Yu-jin and NCT's Doyoung.

[23] Studio MaumC announced Yeonjun as part of the artist lineup for the OST of the Coupang Play original series Cinderella at 2 AM on August 16, 2024.

[26] A video titled "Yeonjun's Mixtape Intro Film" was uploaded to the Hybe Labels official YouTube channel two days later, with his September 19 debut date revealed at the end.

[42] In May 2024, Yeonjun donated 50 million won to Hallym Burn Foundation, an organization dedicated to assisting firefighters in their crucial line of duty.